PC ComponentsCooling

What Is a Heat Sink in a Computer?

Pc Heat Sink

One of the challenges that most electronic devices face is overheating. A computer’s central processing unit (CPU) is not an exception, as some of its components are susceptible to overheating, which can affect the entire functionality of the system. To deal with this issue, a heat sink is introduced. So, what is a heat sink?

Quick Answer

Technically, a heat sink is the component of a computer that helps boost the heat flow out of it when it’s hot. It increases the computer’s working surface area and the volume of low-temperature fluid that flows across the enlarged surface area. 

Aside from the world of technology, a heat sink is a common form of thermal management in other areas, including natural systems and machinery. Since the importance of a heat sink cannot be underemphasized, we’ll unveil several details about it in this article.

About the Heat Sink in a Computer 

A computer’s heat sink is on top of the chip (such as a CPU). It’s a piece of metal that draws power away from components by allowing it to increase via a series of fins. In other words, a heat sink is a device that uses a fan or any related mechanism to minimize the temperature of a hardware component. 

You should note that a heat sink doesn’t need to have moving parts. But at times, it incorporates a fan that helps reduce heat by blowing away the hot air or a liquid cooling solution that takes the heat halfway via the pipes.

You may not yet be convinced about the purpose of a heat sink. Let’s clarify that. The central processing unit (CPU), power supply, and video card are the main components that generate the most heat in a computer. Other components are memory, south bridge, and north bridge. But it is common to see a heat sink on hard drives and other expansion cards

A CPU is susceptible to overheating due to some of its components producing heat. If there is no heat sink, there won’t be a way the heat generated by these components will be reduced in the CPU, which will eventually fry or burn it.

Moreover, most components absorb heat easily because they are made of electronic chips. They can end up damaged (affecting the high performance of the computer) if exposed to excessive heat. But with a heat sink, the CPU can remain cool even after being used for an extended period. 

A heat sink is primarily made to absorb the heat from the CPU and blow it away from its components – the fins that come with the heat sink help make the heat dissipation possible, ensuring that there is more surface area during the heat transfer.

To maximize cooling, a heat sink must firmly contact the heat source. The device uses a thermal conductor that helps transfer heat into fins, dispersing heat in every part of the computer.

How a Heat Sink Works in a Computer 

A heat sink is designed to move heat away from a critical component. This operation is executed in four steps. The first step is how the source generates heat. What could the source be? It can be any system that produces heat that needs to be removed to work correctly. This source can be chemical, electrical, mechanical, solar, nuclear, or friction.

The second step is how heat is transferred away from the source. Heat flows in direct heat sink-contact applications away from the source into the heat sink through natural conduction. The thermal conductivity of the heat sink influences this process directly. This explains why high thermal conductivity materials like aluminum and copper are prevalent in the design of heat sinks.

The third step is how heat is distributed in all parts of the heat sinks. Naturally, heat moves via the heat sink through natural conduction, flowing across the thermal gradient to a low-temperature environment from a high-temperature environment. This implies that the thermal profile of the heat sink will be inconsistent. Consequently, the heat sinks will be hotter persistently toward the source and cooler toward the extremities of the sinks. 

The fourth step is how the heat is transferred from the heat sink. In this step, the primary factor is the temperature gradient of the heat sink and its working fluid, usually a non-electrically-conductive liquid or air. This fluid flows through the warm heat sink’s surface, removes heat from it using thermal diffusion and convection, and transfers it into the surrounding environment. 

How Does the Heat Sink Complete Its Function?

In the final stage, a temperature gradient helps eliminate the heat from the heat sink. So, there won’t be convection and subsequent heat removal if the surrounding temperature is not cooler than the heat sink.

Also, a large surface area offers an increased area for the occurrence of convection and thermal diffusion at this final stage.

Heat Sink Types in a Computer 

Technically, heat sinks have three major types. The first is the passive heat sinks. This type relies on natural convection. Here, no control systems or secondary power is needed to remove heat from the system. Nevertheless, these heat sinks are less effective at moving heat from a system than active heat sinks. But they are still 100% reliable.

The second is active heat sinks. This type uses forced air to boost fluid flow across the hot zone. The items that can generate forced air include a blower and fan. For instance, the fan will help force the air across the heat sink, enabling more unheated air to flow on the heat sink surface, which boosts the thermal gradient and allows more heat to move out of the overall system.

The third is hybrid heat sinks. This type unites both the first and second heat sink types. Hybrid heat sinks usually depend on cooling systems to make the system cool according to the temperature requirements. The forced air source becomes inactive when the system functions at cooler levels – the system is only cooled passively here. But the active cooling mechanism is activated when the source gets to higher temperatures to boost the system’s cooling capacity.


You can’t underemphasize the importance of heat sinks as they play a significant role in ensuring that your CPU is cooled, thus guarding against overheating. With this, there won’t be any heat-related issues with the physical surfaces of critical components and parts.

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